1. Field of the Invention
The present invention relates to a parcel of a deoxidizer and, more particularly, to a parcel which contains a deoxidizer for long preservation or package of goods such as foodstuffs, garments and drugs.
2. Description of the Related Art
In recent years, a method has been used widely for storing and preserving various goods such as foodstuffs, garments and drugs, by keeping such goods in a sealed system together with a deoxidizer which removes oxygen in the sealed system.
Usually, the deoxidizer in such a sealed system is contained in a small sack or parcel with gas-permeable wall. It is preferred that the material of the parcel enables the gas- or oxygen permeability to be adjusted as desired.
To comply with such a demand, various parcel materials have been proposed hitherto. For instance, Japanese Utility Model Post-Examination Publication No. 44-20879 discloses a laminated sheet material composed of a paper having a large gas-permeability and a polyethylene film having a multiplicity of tiny pores, the paper and the polyethylene film being heat-bonded together. On the other hand, Japanese Patent Post-Examination Publication No. 60-37791 discloses a laminated sheet material composed of two plastic films with tiny pores superposed on each other through the intermediary of a sheet of water-proof paper.
These known materials, which employ plastic films and paper sheets bonded together by heat and pressure, suffer from a common disadvantage in that the tiny pores in the plastic film are refilled or deformed by the heat and pressure applied during the bonding with the result that the gas-permeability of the sack fluctuates greatly. Another problem is that the laminated sheet materials exhibit only a small resistance to any force which acts to delaminate the plastic film and the paper sheet from each other.